Peanut allergen proteins Ara h 1, Ara h 2, and Ara h 3 (Ara h 1, Ara h 2, Ara h 3)

Ara h 1, Ara h 2, and Ara h 3 are the primary seed storage proteins of the peanut (Arachis hypogaea) and serve as the major allergens responsible for severe IgE-mediated hypersensitivity reactions. Ara h 1 is a 7S globulin of the cupin superfamily, Ara h 2 is a 2S albumin of the prolamin superfamily, and Ara h 3 is an 11S globulin of the cupin superfamily (UniProt P43237, Q6PSU2, O82580). These proteins are characterized by high stability against thermal denaturation and proteolytic digestion, which enhances their ability to sensitize the immune system and trigger mast cell degranulation (Bublin et al., 2014, Molecular Immunology). Ara h 2, in particular, is recognized as the most potent predictor of clinical peanut allergy. In a therapeutic context, these proteins are the active components in oral immunotherapy (OIT) and epicutaneous immunotherapy (EPIT) products, such as the FDA-approved Peanut (Arachis hypogaea) Allergen Powder-dnfp (FDA Palforzia Label). These treatments work by gradually exposing the patient to controlled amounts of the allergens to induce desensitization, thereby increasing the threshold for allergic reaction and reducing the risk of anaphylaxis upon accidental ingestion (NIH/NIAID).

Other names

Vicilin-like proteinConglutin-like proteinGlycinin-like proteinArachis hypogaea allergens7S globulin2S albumin11S globulin

Induction of immune desensitization and tolerance through gradual exposure, leading to a shift from Th2-mediated allergic responses to Th1/Treg-mediated tolerance and increased allergen-specific IgG4 levels (FDA Palforzia Label; NIH/NIAID).